I found this thread last night as I was searching for headlight removal info....so I just wanted to post what I ended up doing.
In order to remove the headlight bulbs or parking light bulbs (this is on our 2007 Yukon, but I assume the Tahoe to be simliar) I assumed (incorrectly) that you had to remove the headlamps like on the pre-2007 body style trucks....which is NOT the case. Rather than removing the bumper (per above) I:
Driver's Side - pealed back the rubber cover that is between the windshield washer fluid reservoir neck and the headlight.....you can squeeze your hand in there to remove/replace the bulbs.
Passenger Side - Remove the airbox (4 Screws) and you have easy access to the passenger side.
Hopefully this is helpful...I went through this in order to install the Mcculloch Be-Xenon kit (which is GREAT btw!).
-Travis